But what if we flip the question on its head and ask how real-life violence worms its way into the pop canon in the first place?

“Narco Cultura,” a properly dispiriting, mesmerizing documentary by Israeli-born photographer Shaul Schwarz, examines the influence of one of the world’s most vicious criminal groups — the Mexican drug cartels — on a mushrooming Latino musical subculture in the United States.

Schwarz, an experienced photojournalist with a poetic flair for the telling image, went out and got the story on the ground. In “Narco Cultura,” almost the only talking heads you’ll see are two men who have never met, but whose lives Schwarz links by threads of shocking contrast you won’t readily forget. Mostly, he toggles between the two men doing their jobs; the juxtaposition tells a story of cultural corruption that will make your hair stand on end.

On this side of the border, Schwarz attaches himself to a swaggering, genial Latino-American father of two who composes narcocorridos — pop songs glorifying the Mexican drug cartels — on demand for paying customers. He dreams of becoming his own version of a hip-hop star, but when we follow him to Mexico, it becomes clear that he’s not exactly a free agent.

The narcocorridos sell like hotcakes at Target and Wal-Mart. Their lyrics lionize Mexican drug traffickers as latter-day Robin Hoods. Perhaps every generation needs its heroes, but Schwarz dispassionately explodes the absurd analogy. Just across the border in Juarez, also known as the murder capital of the world, he tags along with a quietly matter-of-fact crime scene investigator as he makes his risky daily rounds of gutted cars and charred or cut-up bodies; almost all of the latter belong to innocent bystanders — men, women, children — whose only crime is that they happened to be on the spot. The authorities are systemically corrupt, often colluding with the drug traffickers in their reign of terror.

Schwarz is unsparing but never exploitive of the gruesome body count. Still, the images that will write themselves on your brain and your heart are collateral. Small boys gather near a crime scene, calmly discussing the methodology of a massacre. An imprisoned trafficker recounts having been forced to kill an innocent woman because it was fatal to show weakness. A bereaved mother, beyond fear now, gives vent to her rage as she pounds a table and asks why no one is protesting.

For a long time, the Mexican citizenry remained terrified into submission. Finally, we see clumps of demonstrators quietly standing in silence with enlarged photos of their lost loved ones. It’s not only their courage that reduces us to silence, but also the fact that they have nothing left to lose.

Meanwhile, at packed concert venues in the relative safety of North America, enraptured young Latinos and Latinas jostle one another for a photo-opportunity with the narcocorridos singers and their AK-47s.

For the record: An earlier version of this review misspelled the director’s last name. TheWrap regrets the error.